Earthquakes frequently rapture piping systems carrying gas, oil, water and other fluids, thereby causing severe safety hazards. In some cases damage caused by earthquakes is magnified by subsequent fires caused by broken gas mains. Therefore, it is important that the flow of natural gas or other flammable fluids in piping systems or the like be automatically stopped as soon as earthquake is detected. The danger of explosion and fires resulting from gas escaping from broken pipelines can therefore be averted.
Various safety devices have been proposed in the past to shut-off gas flow upon occurrence of an earthquake. However, prior art devices suffer from several deficiencies. Some are not tamper-proof. Others are not hermetically sealed to prevent the internal components from deterioration from moisture, dust, corrosion, etc. Still others are relative too sensitive to minor disturbances. Also, some prior art valves are relatively easily reset, which may cause additional danger not apparent to the untrained user.
In view of the above, there is therefore a need for a safety cut-off device that will respond to earthquake shocks or other similar motions to stop the flow of gas, oil, or other fluids deemed necessary to mitigate fire hazards or other safety related risks after the occurrence of an earthquake, without the shortcomings of prior art devices.